<div class="change-grand-son">
  <h4>这是孙子组件</h4>
  <button class="btn btn-success" (click)="grandSonName = '蛤蟆'">change grandson name</button>
  <p>孙子名称： {{ grandSonName }}</p>
  <p>位置： {{ position }}</p>
</div>
